Comparison of sorption performances of the present study and other reported literature.

Sorbent	Element	Enrichment factor	LOD (μg L−1)	RSD (%)
Polyethylene glycol loaded on silica gel (SiO2@PEG)54	Cu(ii), Cd(ii), Mn(ii)	66.6	0.33–1.20	3.42–4.91
Dithioxamide onto activated carbon (AC@DTO)55	Ni(ii), Co(ii), Cu(ii)	330	0.5–0.8	<2
1-(2-Pyridylazo)-2-naphthol loaded on silica gel (SiO2@PAN)56	Cr(iii), Mn(ii), Fe(iii), Ni(ii), Cu(ii), Cd(ii), Pb(ii)	80–150	0.13–4.1	5–26
Thiosalicylic acid loaded on silica gel57	Pb(ii)	150	3.7	<1.5
Dihydroxybenzene loaded on silica gel58	Cu(ii), Pb(ii), Fe(iii), Zn(ii), Co(ii), Ni(ii), Cd(ii)	250	4	1.4–7.0
Amberlite XAD-2010 resin59	Mn(ii), Co(ii), Ni(ii), Cu(ii), Cd(ii), Pb(ii)	100	0.08–0.26	1.9–5.1
This work: (SiO2–(CH2)3– Im– C18)	Cr(iii), Ni(ii), Cu(ii), Cd(ii), Pb(ii)	60–150	0.724–11.329	0.941–1.351